DE1698126B2 - Device for the calibration of pressure gauges - Google Patents

Description

* 5

The invention relates to an apparatus for calibration of pressure gauges with an a: pivotable solid waagercchte axis balance beam, with such a means for applying a variable pressure to a piston in a liquid as well as with Emrichtungen for transmitting the Fiüssjgkeitsdrocks • ta Ann the balance beam and the Device to be calibrated, with one connected to the other Ann of the balance base k ddl di h

kens arranged and displaced along this Anne- MldEiklA

»Ad nut enter dorcb 4m" gs Steueracr

g fSt den Feisdrock in the sense of WtedartasKttaag des Gtekfagcwin Wdft bei dkaet am der ÜS- ¥ S H , with the star calving fulfilling the role of a slide, which is arranged between a pressure fluid jceitsqeelle and efoero drain and is coupled with the scales.

From US Pat. No. 2,992,302, a toe device has become known in which the balance base is unbalanced by the excitation of solenoid control valves when the control valves are connected to supply channels for the pressure medium (here compressed air).

U.S. Patent 2,446,740 discloses a calibration device with a reversible air pump, which is automatically dependent on the closure of an electric Circuit can be put into operation by a float, the float being dependent The pump shaft can be pressed against a height-adjustable guide rail as a measurable pressure In addition, at any time in a cylinder a pressure that corresponds to the displayed pressure and that of a manometer to be calibrated is abandoned. However, a balance beam is not provided.

The invention is based on the object to train called device so that it better than before the various requirements corresponds to practice in that it carries out this calibration precisely, faithfully and practically automatically, with the value of the pressure actually applied to the apparatus to be calibrated automatically (after stabilization the moving parts of the device) exactly on a display device that is independent of the apparatus is displayed and in the whole range of the operating pressure of the apparatus by simple pivoting of an actuation gnff can be changed and set. This goal is achieved according to the invention achieved in that the piston of the control device which is in contact with the pressure fluid for the liquid, pressure by a motor that can be operated in both directions of rotation with the interposition of the rotation of the engine in a translational movement converting transmission system is linearly movable and that in the excitation circuit of the motor electrical switches are arranged by the balance arm in such a way are switchable that the motor siets in one of the Balance beam is excited in its equilibrium position returning the direction of rotation. This will achieves that the calibration device is characterized by the simplicity of manufacture, the robustness, which is essentially due to the piston mechanism and the screw gear mechanism as well as in performance in terms of accuracy and reliability

The electrical switches are advantageously designed in this way. that they can be actuated by the balance beam without mechanical contact with it.

The invention is explained below with reference to the drawing beispklsweae, in which 3 i ld Si Ü

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Fi ^. 1, 2 and 3 a lotted section Üejt lime 1 * 1 diet 'Fig. 3 or .. a vertical section Btap of the line 1MB of Fig, 1 or a from above idb Taansidit a »device for calibration

16S0736 bsat) m wild «aa Wtajytiilton dardi die aaaitteftftnu Lagever * id dSte» erkoibais aas dem GkkJietwkbt

It is well known that manometer by means of a hand-held Balke scales m «even, ba wekher da» fjMd% tmet & de * balance beam is either dadarefa bergötOt that the weight is applied to di bi vetschobeo by hand, ödet dadoidi, fa Dh i H

that daicfa turning a handwheel «by hand

3 4

simultaneously on the balance beam and d 's m-calibrating and their interconnections is a liquid Rait

Manometer acting pressure of a liquid ver8- ture 45 filled.

there will. j ^ _T piston 34 is outside chamber 30

line such Vorrichfcrag is imprecise, and its extended by a threaded bolt 35 un <t by

Application is tedious, since only with successive 5 its attachment to one in a corresponding

low approximations can be worked. Bore 37 of the frame sliding parallel rod 36

It is also known to constantly measure the pressure of a rotation, but not an axial TransGas by means of a beam balance, with a curative movement

rather the imbalance of the balance beam. The threaded bolt 35 acts with a nut 38

automatically used to put together the weight of io, which through their installation in a cnt-

to move this in the sense that the speaking bearing 39 of the frame on an axial

Balance restores translational motion, but not rotation The calibration of precision manometers is prevented by means of This nut has a worm screw on the outside

Such an automatic gear toothing can be a hydraulic fluid and acts with one on the shaft

tables, only the position of the weight influencing 15 of an electric motor 41 attached screw 40

Scheme does not work properly as they are not strictly related.

which can compensate for the errors, giving way to the leakage This motor can vary depending on the nature of its excitation

flows of liquid along the piston, the inlet through the closure of one or the other of

compressibility of the liquid and any two electrical switches 42 and 43 in one

Deformations of the pipelines result. ao or the other sense in rotation

This absolutely necessary compensation will become auto- matic.

automatically obtained by the fact that the scheme is directly 1 embodiment shown

bar influences the pressure of the liquid. these switches become immediately from the end 44

In the embodiment shown, that of the longer arm of the balance beam 4 is actuated. she

Calibration device a z. B. by two by columns 3 as are of course arranged so that by their

braced horizontal plates 2 formed solid closure generated movement of the motor the

put I ₁ which moves a 5 balance beam around a horizontal axis into the equilibrium position (ie in

pivotable rigid balance beam 4 carries (Fig. 1 general in its horizontal position) returns,

and 3). as explained below.

This balance beam consists of two through 3 <> Each position of the weight 7 on the verse of the balance 6 braced parallel strips. bar corresponds on the one hand to an exactly

One arm of the balance beam (right arm in Fig. 1 correct value of the pressure of the liquid 45 in the

and 3) carries a weight 7, which with rollers 8 to balance the balance beam and on the other hand

the last rolls. This weight contains a precisely defined angular position of the handwheel

Threaded bore 9, which is connected to a cross member 6 35 11 and its shaft 13.

stored, extending parallel to the bars. For this reason, this wave is z. B. over a

Threaded spindle 10 cooperates. Bevel gear 46, 47 with the input of a numerical

The rotations of this spindle and thus the counter 48 connected, which was previously calibrated shifts of the weight 7 along the Waagebai- that he immediately kens the equilibrium 4 by the rotations of one at the 4 ° of the balance beam for the various angles -Frame attached handwheel 11 with vertical lungs of the handwheel corresponding exactly axis over a fixed with the shaft 13 of the handwheel correct pressure values. This previously connected worm 12, a calibration in engagement with it, can easily take place in that a calibration manometer is used as the manometering worm wheel 14 and a universal joint meter 32,
45 In the figures, adjustable feet 49 and worm wheel 14 are visible through a shaft of the frame that can be rotated in a bearing 17 with a spirit level 50 for the horizontal adjustment of the horizontal axis in the frame.

16 is firmly connected, while its other part 18 The above device works as follows:

is firmly connected to the threaded spindle 10 and after the pressure of the liquid 45 on the

The center of its cross piece 19 was brought to the pivot 50 atmospheric pressure, is attached to the

axis 5 of the balance beam is. Circle this liquid around the mahometer to be calibrated

The other arm of the balance beam (left arm included in 32, whereupon the feet 49 are so adjusted

Fig. 1 and 3) carries a bracket 20, which will be on one that the frame horizontal ^f . lies.

Axis 21 of the balance beam is suspended and free. The handwheel 11 is then turned until a

through window 23 of the upper plate 2 occurs. 55 given pressure of z. B. 10 bar at the counter 48

At the base of this bracket is supported by a display.

Ball 24 (Figs. 1 and 2) off a piston 25, which thereby moves the weight 7 to the right

pushed freely without play in a cylinder 26 of the frame,

slides. Since the pressure of the liquid 45 is not sufficient,

Ufes the base area of the column facing away from the sphere by the moment generated by this displacement Ben is located in a chamber 27, which is to be compensated by, the right arm of the fixed lines 28 with two other chambers 29 bar goes down, whereby the switch 4ί is closed and! 30 of the frame is connected to the Kam- will.

mer 29 stands with the pressure-sensitive space Jl This closure excites the motor 41 ra dem

of the manometer to be calibrated 32 Hi connection. 65 sense in which the piston 34 enters the interior of the

Through the wall of the chamber 30 a zylitt- chamber 30 is pushed back, whereby the pressure

drical bore 33, which contains a piston 34. the liquid 45 is increased.

The volume of the chambers 27, 29, 30 and 31 This increase in pressure pushes the piston 25 and

the bracket 20 downwards, whereby the left arm ment, they can in particular be designed so of the balance beam 4 is lowered. that they are from the balance beam without mechanical

When the equilibrium is re-established, open touch with the same operated, net the switch 42, the motor 40 stops, and so they can, for. B. be formed by relays,

the balance beam stops. s which by lighting or stopping the

One is then certain that the pressure exerted on the manometer by light beams from photocells is equal to the pressure read, which is 10 bar from the balance beam, so that the dial of the manometer is at least partially covered according to its position In that of its pointer will be 51 right now.

assumed position with a corresponding io The movements of the balance beam can also Graduation can be provided. the desired contacts through magnetic or

The processes are of course the same for all inductive effects other pressure values. Likewise, the control of the sliding movement of the

You can also operate the handwheel piston 34 by other than electromechanical 11, wherein the balance of the balance arm 15 means take place, for. B. hydraulic or pneumatic appropriate stabilization is awaited by funds.

the pointer S1 on which is already divided with a division. The above training can still be improved

See the dial of a manometer 32 given by the arm of the weight 7 bearing the values, and then the real balance beam is made of a material, the corresponding values of the counter 48 read to the 10 linear thermal expansion coefficient K ₁ dop error of these Determine the display and possibly as large as the coefficient K _t of the piston, if a correction table should be drawn up. 25 (and the cylinder 26 accommodating it)

It should be noted that the value of the pressure is the material, while the other arm is the Liquid 45, in which the balance beam is located in the balance beam made of a material with a comparable equilibrium, is always exactly equal to the value indicated by the counter 48, which is then a negligible coefficient of thermal expansion. This ten exists.

Because pressure is the only one for that on the left. This training creates balance

Arm de * balance beam unexperienced moment measure of the balance beam from the fluctuations of the space-giving variable size (the cross-section of the temperature independent.

Piston 25 and the length of the lever arm between 30 The moment acting on its first arm depends on the axes 21 and 5 remain constant) and diii An namely on the temperature t by a factor of this displayed value are due to the 1 + K, f , while the mass of the weight 7 confronted training remains constant exactly to the displacement.

proportional to the weight 7 on the balance beam. That moving to the other arm of the balance beam is the only variable variable which corresponds to the practiced moment "far from the product of a lever arm which can be moved to the right arm of the balance beam and a crane, wv." ... * decisive is, provided that it is naturally proportional to the area of the piston 25, that the original calibration of the balance, which is the pressure of the liquid, acts. Dipeo "- <· <bar was made in such a way that if the count now depends on the temperature by a factor 48, it shows zero and thus the weight 7 is at 40 (1 -f K ₂ O *, its value practically equal to 1 + 2 K _t i occupies the position furthest to the left, which is, i.e. ultimately equal to 1 + K ₁ I. The two balance bars lie horizontally, when the pressure in the desired moment depends on the temperature chamber 27 has the value zero by the same factor, so that the consequences are dei (this value corresponds to the atmospheric pressure, thermal changes on the equilibrium de; if the pressure gauges 32 are calibrated in relative values 45 balance bars are automatically balanced, or the absolute vacuum, if In the version shown, the first *

Absolute bets are calibrated). Arm of the balance beam, d. H. the screw lockers

The indicated value aängl to particular in none 10, exist in the duralumin (whose coefficient K way of the depth of the entry of the piston 34 is in the order of magnitude 23 -10- *), the chamber 30 or that in the chambers 27 to 31 50 of the second arm by two in the strips 4 is present amount of liquid. The device put plates52 (Fig. 2 and 3) made of Invar building, thus ensuring an automatic, precise output, and the piston 25 and the cylinder 26 are equal to the leakage flows of the liquid along the steel (K _{2 in the} order of magnitude 12 · 10- «) Pistons, the compression force of the liquid, the embodiment can of course be varied and deformations of the pipelines. 55 delt. So z. B. the two arms de In the Ausfohnmg shown in Fig. 1 balance beam, to soft the force of the moveable switch 42 and 43 through mechanically actuated by the weight or the counterforce of the pressure fluid balance beam contactiareellen formed, they ei, on the same Side of the pivot axis can of course also be arranged on any other side of the balance beam, in which case the desired manner can then be formed. 60 force generated by the pressure of the liquid according to

According to an advantageous Ausfühnmgsabwand- is directed upward instead of downward For this purpose 2 sheets of drawings

Claims (2)

L device an- Etdtun * vou manometers with Sw * e ££ Κΐ ^ axis swiveling balance beam, with a Einriehtung * ur exercise of a controllable * Pw * s with eüem piston »if a liquid w as with eightions we transfer the liquid pressure to an arm of the Balance beam and the "o τα calibrating device, with a heavy mass arranged on the other arm of the balance beam and displaceable along this arm, with a device for attracting the liquid corresponding to every position of the heavy mass on the balance beam keitsdrucfcs and with one by the weight disturbance of the balance beam controllable device cur automatic actuation of the control device for the liquid pressure in the sense of the * o restoration of the state of equilibrium of the balance beam, characterized in that the piston (34) in contact with the pressure fluid (45) of the control device for the liquidity sun, one in both directions of rotation An operable motor (41) can be moved in a straight line with the interposition of a gear system (35 to 40) which converts the rotation of the motor shaft into a translational movement and that electrical switches (42, 43) are arranged in the excitation circuit of the motor, which are controlled by the balance beam (4 ) are switchable in such a way that the motor is always excited in a sense of rotation which returns the balance beam (4) to its equilibrium control. 2. Eichvorrichtumg according to claim 1 thereby characterized in that the electrical switches are designed so that they are from the balance beam without mechanical contact with iSesem beti% - * c are cash. * ""